The invention described herein may be manufactured, used and licensed by or for the government for governmental purposes without the payment to us of any royalties thereon.
Portable mats for use as portable bedding materials have long been known in the art. From earliest times mats of, e.g., straw, feathers, etc., have been used as bedding materials. In most recent times, inflatable mattresses and mattresses formed of polymeric foam have been employed. Mattresses formed of closed-cell foams are particularly desirable since they afford relatively high degrees of insulation.
However, while such mattresses offer the advantage of high insulation properties and relative portability, they possess the disadvantage that they are difficult to readily fold and when folded or rolled still retain substantial bulk. A further disadvantage of closed-cell foam mats resides in the trade-off between bulk and comfort; low bulk mats provide less cushioning.
Durable closed-cell foam sleeping mats have been adopted as standard items by the military of many countries and have also found widespread use among sports persons because of their high insulation, light weight, durability to the rigors of field use and for their water-imperviousness. However, they are not as comfortable as air-mattresses and other sleeping devices and are bulky and awkward to carry. Both of these disadvantages result from their relatively incompressible closed-cell foam construction which is necessary to provide thermal efficiency, insulation, water imperviousness, and durability.
In an attempt to overcome these deficiencies, mats have been constructed in segmented panels such that they can be folded in various rectangular configurations which are less awkward and slightly less bulky than a typical rolled tube configuration discussed above. However, these configurations provide no comfort improvement.
In an attempt to improve the comfort provided by such mats, while retaining the relatively incompressible closed-cell foam structure, mats have been manufactured in a "ridged" construction (as opposed to a perfectly flat construction). The ridges or hills and valleys significantly increase both the effective thickness of the mattress and the compressibility/resiliency of the mat, thereby substantially increasing the comfort provided by the mat, while retaining its basic insulating and durability characteristics. Unfortunately, this comfort advantage is achieved at the expense of a considerable increase in bulk, in either rolled or folded panel configuration. Accordingly, previous portable sleeping mat constructions and configurations do not provide the optimum comfort level while still allowing for optimum low bulk storage and affordability.